I think the point was that Python, as a language and ecosystem, has experienced a number of breaking changes over the years. In practice, that means code written only a few years ago may no longer run without specific versions of Python and a collection of dependencies, many of which have since been replaced by newer, incompatible implementations.
What I appreciate about the traditional shell languages is their remarkable stability. Shell scripts written in 2000, or even earlier, are often still able to run today with little or no modification. By contrast, Python applications frequently require recreating a historical runtime environment, including older language versions and dependencies, many of which have accumulated significant security vulnerabilities over time.
Interestingly, apart from the various shell languages, Perl is probably one of the strongest alternatives in this regard. The Perl community has placed a high value on backward compatibility, allowing older code to continue functioning while the language itself remains actively maintained and up to date.
I basically agree with these tradeoffs (you should never be pulling in dependencies outside the builtins), but let's look back to GP:
> Comparing the shell to C, Go, Rust, Python, or JavaScript is crazypants. It has a different job than those, so of course it will look and feel different!
The point was just a small one, that Python is not like the others. C, Go, and Rust do not come with REPLs. Node is plausible to use as an OS shell but I've never heard of anyone doing that. Python is the only one of those I've used as a shell or have heard of others using as a shell.
Again, I'm not advocating for Python as a good general-purpose shell. I'm only making the small claim that C, Go, Rust, and (to a smaller extent) JavaScript cannot be be used like bash. Python could be used as a shell.